1. Field of the Invention
The present invention relates to a pipe insulation sleeve made of mineral wool bound by a thermosetting binder. The term "mineral wool" is here used to mean any kind of wool of mineral material, such as glass wool, rock wool, slag wool. The invention further relates to a method of making such a pipe insulation sleeve and to an arrangement for carrying out the method.
2. Description of the Prior Art
Mineral-wool pipe insulation sleeves are customarily made by winding a thin sliver of raw mineral wool impregnated with a thermosetting binder around a tubular core of the desired diameter until the desired insulation thickness is attained, and then hardening the raw insulation sleeve at a temperature of approx. 200.degree. C., for example by blowing hot air through the wool via the core. The binder hardens, thereby fixing the shape of the sleeve.
The cylindrical sleeve is usually slit in the longitudinal direction so as to produce two halves connected to each other along one side. In installation the two halves are forced apart and pushed over the pipe, after which they are bound together in suitable fashion and possibly also fitted with an outer covering. Larger diameter insulation sleeves can be divided into two or three separate parts in order to achieve a smaller packing and transport volume.
The manufacture of small and medium-sized pipe insulation sleeves with an inside diameter less than about 300 mm and an insulation thickness less than about 100 mm can be carried out fast and efficiently on highly automated machines.
When, however, large pipe insulation sleeves are concerned, such as those for district heating mains which can often have insulation thicknesses greater than 100 mm, the production capacity is low because the hardening times become long and also the winding of the sliver of mineral wool onto cores of large diameter is time consuming.